In Patent Document 1, for example, there is disclosed a supporting structure for a crankshaft of an internal combustion engine.
A main journal part of the crankshaft is rotatably supported by a main bearing part constructed from a cylinder block and a bearing cap secured to the lower side of the cylinder block.
The bearing cap is fastened to the cylinder head by two fastening bolts disposed on both sides of the main bearing part. In general, these two fastening bolts are secured with an equal axial force, and located to have an equal distance from the main journal part when viewed from an axial direction of the crankshaft.
If the two fastening bolts disposed on both sides of the main bearing part are designed to have the same axial force, however, the axial force to be determined should be brought into conformity with the side requiring a greater axial force, and therefore one side of the main bearing part is to be secured with a larger axial force than necessary.
Thus, conventional internal combustion engines are susceptible to further improvement in securing the bearing cap to the cylinder block, so as not to generate a gap at the bearing cap.